A packaging machine is typically a device for strapping articles by packing belts. The packaging machine generally includes a machine core device for hot sticking and shearing packing belts, a frame mounting for winding binders by packing belts. The packaging machine is provided with a packing belt tensioning roller set, a belt feeding roller set and a belt pre-feeding roller set before the machine core. The whole packaging process includes steps such as belt feeding, belt retreating, tensioning, hot sticking and shearing. Generally both belt feeding and belt retreating are realized by their own roller set. A roller set generally consists of a drive wheel and a driven wheel which can engage to and disengage from the drive wheel. Previously, a mechanism for manipulating the driven wheel of a belt feeding and retreating roller set to engage to and disengage from the drive wheel is complex in components, heavy in weight, easy in terms of causing over-vibration in the process of belt feeding and retreating, thus causing belt feeding and retreating unstably and affecting the packaging and strapping effect. In a belt tensioning roller set, it is difficult to pre-adjust the pressure between the drive wheel and the driven wheel. The belt tensioning mechanism may apply either too much or insufficient tensioning force on different packing belts.
In general, the structure of the conventional packaging machine needs improvement for matching the packaging efficiency, operation reliability and packaging quality.